OBJECTIVE To catalog SIV CTL epitopes DISCUSSION There is accumulating evidence to suggest a key role for CTL in the containment of HIV and SIV infections. As such, there is considerable interest in developing vaccines designed to induce virus-specific CTL responses. Various macaque species, most notably the rhesus macaque, have been used extensively to study AIDS virus pathogenesis and vaccine efficacy. As a result of these studies a number of SIV and SHIV CTL epitopes, and their restricting MHC class I molecules, have been identified. Accurate definition of these CTL epitopes, however, is critical both to the development of vaccines as well as to the construction of MHC class I tetrameric complexes which have revolutionized our ability to measure CTL responses to individual CTL epitopes. In this list, only the Mamu-A*01 restricted CTL epitopes have been optimally defined through the use of peptide dilutions and knowledge of Mamu-A*01Us peptide binding motif. The other epitopes listed in Table I have been identified thro ugh the use of overlapping peptides, however, their optimal lengths have yet to be determined. In Table II additional CTL epitopes are listed for which the restricting MHC class I molecules have yet to be identified. Furthermore, the majority of these epitopes have only been mapped using overlapping 20mer peptides. It will be important to define both the restricting MHC class I molecule of these epitopes and their optimal length if they are to be considered for use in vaccination trials or tetramer construction. FUTURE DIRECTIONS The expansion of this list will be very important to studies designed to examine the role of CTL in AIDS virus infections and the effectiveness of CTL-based vaccines. KEY WORDS FUNDING NIH RR00167, AI32426, AI41913, AI42641 PUBLICATIONS Allen, TM and D.I. Watkins. 1998. SIV and SHIV CTL epitopes identified in macaques. In HIV Molecular Immunology Database 1998; B. Korber, J. Moore, C. Brander, R. Koup, B. Haynes, B. Walker, Eds. Los Alamos National Laboratory, Theoretical Biology and Biophysics Los Alamos, NM. pp. IV-8 - IV-13.